The latest Fedora development snapshot makes Ext4 the default file system and adds experimental support for the next generation btrfs filesystem. "According to current plans, version 11 of Fedora, which is expected to arrive in late May, will use Ext4 as its standard file system. That's what the Fedora Engineering Steering Committee (FESCo) recently decided, following a heated discussion in an IRC meeting. If however Ext3's successor encounters big problems with the pre-release versions of Fedora 11, the developers will dump that plan and revert to Ext3."

why should I care what file system my computer uses? what difference does EXT4/EXT3/Fat32/ntfs really make.

As an end-user will it really matter?

As a JOE you shouldn't care. You might experience slightly better performance with ext4 and hopefully no data loss. In general the distro developers should choose the "best" defaults for you. Which is why I'm a bit worried, but curious at the same time.